CVE-2026-84992Public exploitNetwork attack vector

Cross-site scripting via unescaped fenced-code language

Published Sep 18, 2026 · Updated Sep 18, 2026

Cross-site scripting in imzbf md-editor-v3 before 6.5.4 allows remote attackers to execute JavaScript through crafted Markdown. The MdPreview useMarkdownIt() highlight callback places the fenced-code language value into class and language attributes without escaping or consistent quoting, while XSSPlugin inspects only preexisting HTML tokens and misses the generated markup. Exploitation requires attacker-controlled Markdown and a victim to render it; persisted input becomes stored XSS in the application's origin.

CVSS severity6.1
Medium
EPSS probability0.33%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in imzbf md-editor-v3 before 6.5.4 allows remote attackers to execute JavaScript through crafted Markdown. The MdPreview useMarkdownIt() highlight callback places the fenced-code language value into class and language attributes without escaping or consistent quoting, while XSSPlugin inspects only preexisting HTML tokens and misses the generated markup. Exploitation requires attacker-controlled Markdown and a victim to render it; persisted input becomes stored XSS in the application's origin.

The record

CVE
CVE-2026-84992
Published
Sep 18, 2026
Updated
Sep 18, 2026
Vendor
imzbf
Product
md-editor-v3
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 6.5.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

imzbf · md-editor-v3version=< 6.5.4

Published CVSS scores

6.1GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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